Writing instrument cap securing means

ABSTRACT

IN A WRITING INSTRUMENT INCLUDING A BARREL OR BODY AND A CAP, AN IMPROVEMENT IN MEANS FOR RELEASBLY SECURING THE CAP TO THE BARREL OR BODY WHEN THE INSTRUMENT IS NOT IN USE INCLUDING THE PROVISION OF A RADIALLY INWARDLY DIRECTED LIP FIXEDLY CARRIED BY THE OPEN END OF THE CAP WHICH RECEIVES THE FORWARD END OF THE BARREL, A CYLINDRICAL RING FIXEDLY SECURED ON THE BARREL AND INCLUDING AT LEAST THREE PROJECTIONS OR DIMPLES GENERALLY EQUALLY SPACED ABOUT THE CIRCUMFERENCE OF THE RING, THE RING BEING SMALLER IN DIAMETER THAN THE DIAMETER OF THE CAP LIP AND THE RADIALLY OUTERMOST PORTIONS OF THE DIMPLES ON THE BARREL RING DEFINING A DIAMETER GREATER THAN THE DIAMETER OF THE CAP LIP SO THAT THE CAP MAY BE FORCIBLY AXIALLY MOUNTED OVER THE BARREL RING PROJECTIONS TO PROVIDE AN AUDIBLE, POSITIVE, SNAP FIT.

May 30, 1972 M. F. REED WRITING INSTRUMENT CAP SECURING MEANS Filed May 6, 1969 10 T Toe/v5 w.

United States Patent O 3,666,373 WRITING INSTRUMENT CAP SECURING MEANS Meuriel F. Reed, Los Angeles, Calif., assignor to The Gillette Company, Boston, Mass. Filed May 6, 1969, Ser. No. 822,253

' Int. Cl. B43k 9/00 US. Cl. 401-247 3 Claims ABSTRACT OF THE DISCLOSURE In a writing instrument including a barrel or body and a cap, an improvement in means for releasably securing the cap to the barrel or body when the instrument is not in use including the provision of a radially inwardly di rected lip fixedly carried by the open end of the cap which receives the forward end of the barrel, a cylindrical ring fixedly secured on the barrel and including at least three projections or dimples generally equally spaced about the circumference of the ring, the ring being smaller in diameter than the diameter of the cap lip and the radially outermost portions of the dimples on the barrel ring defining a diameter greater than the diameter of the cap lip so that the cap may be forcibly axially mounted over the barrel ring projections to provide an audible, positive, snap fit.

BACKGROUND AND PRIOR ART Many types of writing instruments, such as fountain pens, ball point pens, and porous point pens, employ a cap which may be releasably secured over the end of the barrel or body from which the Writing tip projects. Such cap protects the user from inadvertently allowing the writing'ink from marking the clothes of the user, such as when the writing instrument is carried in the pocket of the user. Since the cap is removed each time the writing instrument is used, it is obviously desirable that the cap be easily mountable and demountable from the writing instrument barrel. On the other hand, it is desirable to provide a secure fit of the cap onto the barrel to avoid accidental dislodgement.

One expedient used in the prior art to effect the releasable secureinent of the cap of the barrel is to provide a non-symmetrical cap which when axially forced upon the cylindrical symmetrical barrel will distort so as to provide a tight, sliding, gradual frictional engagement. Inother words, as the cap is axially forced onto the barrel, the frictional resistance is relatively constant or only slightly increasing until the cap is fully secured on the barrel. It is also known in the art to reverse these complementary elements by providing a symmetrical cap with a non-symmetrical ring fixedly secured on the barrel. In Pat. No. 2,602,422, there is shown such construction wherein the cap opening diameter is less than the major axis of the non-symmetrical ring and greater than the minor axis of such non-symmetrical ring so as to be gradually frictionally engaged when the cap is mounted on the barrel.

Another type of gradual, relatively constant required force, frictional engagement is shown in Pat. No. 2,278,- 907 wherein the cap is provided with an inner sleeve having a plurality of bowed spring fingers providing yieldable gripping surfaces engaging a metallic clutch ring mounted on the barrel. A similar type of securing means is .shown in Pat. No. 2,398,521 wherein an inner sleeve supports inwardly bowed arms which engage a ring mounted on the barrel.

3,666,373 Patented May 1972 GENERAL SUMMARY OF INVENTION It is a general object of the present invention to overcome the disadvantages of the prior art writing instrument cap and barrel securing means through the provision of improved securing means which does not utilize gradual, relatively constant frictional force engagement to effect the securement.

It is an object of the present invention to provide improved securing means for the barrel and cap of a writing instrument which has positive locking action through the use of interference between a lip carried by the open end of the cap and a ring, having dimples or projections, secured to the barrel.

Another object of the present invention is to provide improved securing means of the last described type in which there is provided an audible click when the cap is secured on the barrel so as to notify the user that the securement has been effected.

Yet another object of the present invention is to provide improved securing means of the abovedescribed type which has long wear characteristics and does not require precise manufacturing tolerances so as to reduce manufacturing costs.

Generally stated, the present invention relates to an improvement in a writing instrument comprising a barrel, a cap and means for releasably securing the cap to the barrel when the instrument is not in use, such improvement comprising an improvement in the securing means including a generally cylindrical metallic band fixedly secured on the end of the cap which receives the barrel and carrying a radially inwardly directed lip, a generally cylindrical metallic ring secured on the barrel and having at least one slot axially extending from one edge towards the opposite edge and at least three radially outwardly directed projections generally equally spaced about the circumference of the ring, the barrel ring being smaller in diameter than the diameter of the cap band lip, the radially outermost portions of the barrel ring projections defining a diameter greater than the diameter of the cap band lip, the barrel being resiliently deformed when the cap lip is axially forced thereover so as to provide a snap fit, and stop means carried by the barrel and cap to limit movement of the cap relative to the barrel after the snap fit is effected.

Other objects and advantages of the present invention will become more readily apparent from the following description considered in connection with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a writing instrument incorporating an exemplary embodiment of the cap and barrel securing means improvement of the present invention;

FIG. 2 is an enlarged detailed sectional view of the cap securing means of the present invention, showing the cap secured on the barrel;

FIG. 3 is a sectional view taken along the plane IIIIII of FIG. 2; and

FIG. 4 is a perspective view of exemplary metallic band and metallic ring comprising cap securing means of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, then is shown a writing in strument indicated generally at 20 comprising a cap 21 and barrel or body 22. Cap 21 is provided with the ordinary pocket clip 23. The cap 21 is secured on barrel 22 by means 25 generally comprising a ring indicated at 30, stop means indicated generally at 36 (see FIG. 2), and a band indicated generally at 40.

With attention to FIGS. 2 through 4, the generally cylindrical ring may be of metal and fixedly secured on barrel 22. Ring 30 comprises a cylindrical portion 31 having a forward edge 32 and a rearward edge 33. The cylindrical portion of the ring is provided with at least one slot 34. In the exemplary embodiment, three such slots 34 are employed each of such slots axially extending from the forward edge 32 of the cylindrical portion 31 toward the rearward edge 33.

The cylindrical portion 31 of metallic ring 30 is also provided with at least three radially outwardly directed domed projections or dimples 35, the exemplary embodiment employing three of such dimples integal with the cylindrical portion 31 and having a convex shape. The dimples 35 are generally equally spaced about the circumference of the cylindrical portion 31, i.e., spaced at 120 intervals and are also somewhat spaced from the edges of the ring 30. In the exemplary embodiment, the slots 34 are circumferentially adjacent to each of the dimples 35.

e The cap securing means of the present invention is also provided with stop means 36 carried by the barrel ring 30 and cap band to limit axial movement of the cap 21 relative to the barrel 22 after the snap fit is effected. In the exemplary embodiment, such means 36 comprises a radially outwardly directed flange 37 formed integrally on the rearward edge 33 of the cylindrical portion 31 of metallic ring 30. The cylindrical ring 30 is secured within a circumferential external recess on barrel 22. As shown in FIG 2, the recess includes a rearwardly facing shoulder 38 on a forward barrel portion 22a against which the for- Ward edge of the ring 30 abuts and a forwardly facing shoulder defined by the forward edge of a second or rearward barrel portion 22b which is axially threaded on and connected to barrel portion 22a. The two oppositely facing spaced shoulders cooperate to form a circumferential recess therebetween so as to secure the cylindrical ring on the barrel and fixedly mount the stop means relative to the barrel. It will be understood, of course, that other stop means may be provided, for example, the forward edge of the barrel portion 22b could be employed as the stop means for the cap. The generally cylindrical metallic cap securing band 40 is attached to cap 21 adjacent its open end portion (which open end receives the forward or writing tip portion of the barrel) and includes a circular wall of ogive-like section extending beyond said open end. One edge of the band has an inwardly and radially directed member 42 which snap fits in an annular groove on cap 21 during manufacture and is fixedly secured thereto. The free edge portion of the cap band includes a radially inwardly directed lip 43 which is axially spaced away from the forward edge of the cap 21. Lip 43 has an inner cylindrical Wall 45 and an end wall 46.

The cylindrical portion 31 of the barrel ring 30, as seen best in FIGS. 2 and 3, has a generally smaller diameter than the diameter of the cap band lip inner wall 45. The radially outermost portions of the barrel ring dimples or projections 35 define a diameter, as seen in FIG. 3, greater than the diameter of the cap band lip inner wall 45. Differently stated, the internal radius of lip 43 is less than the axial radius of the outermost portions of domed projections 35. Accordingly, it will be seen that the barrel ring 30 is resiliently radially deformed when the cap band 40 is axially forced thereover so as to provide a snap fit. Axial movement of the cap relative to the barrel will be limited by the stop means 36.

The axial length of inner wall 45 of cap band lip 43 will be seen from FIG. 2 to be less than the axial length i 42 2 3; from the surface of flange 37 to the outermost point on the dimples 35. Thus, when the cap is secured on the barrel, the lip 43 of the cap band 40 extends radially inwardly of the outermost portion of the dimples 35 on ring 30 after such ring has assumed its normal shape subsequent to the slight deformation attendant thereto during axial forcing of the cap onto the barrel.

It should be appreciated that the provision of the axial slots 34 in the barrel ring 30 are provided to relieve the stringent manufacturing tolerance requirements that would exist without the slots. That is, the slots obviate the. requirement of maintaining extremely close tolerances in the diameter of the inner cylindrical wall 45 of the cap band lip 43 and the roundness of the band lip, as well as such tolerances for the dimples 35 on the barrel ring 30. It should also be noted that an audible click is pro duced by the use of a metallic band and ring which indicates to the user that the securement has been eflected. The click is believed to be produced by the abutment of the front wall 46 of the lip 43 against the flange 37. Moreover, in the embodiment shown, the cap is tightly axially secured on the barrel and prevented from slight axial movement or play since the dimples 35 are closely adjacent the flange 37 so that the axial distance therebetween is less than the axial length of the inner wall of the cap band lip 43. In this manner, the sloped portion of the dimple constantly urges the cap against the flange, as seen best in FIG. 2. i g

It will also be appreciated that when the cap is forced on the barrel, the frictional force resisting such axial movement will be rapidly increasing as required to'deform the ring dimples a greater amount for each increment of axial movement. When the lip of the cap band passes the highest point of the dimples, however, the force required for axial movement is actually aided by the force applied to the cap hand during subsequent return of the barrel ring from its deformed shape. This provides the snap action which assures the occurrence of the audible click and prevents accidental dislodgement of the cap from the barrel when the instrument is not in use. e

Other modifications and variations of the present invention are possible in light of the above teachings. It is there fore to be understood that within the scope of the appended claims, the inventions may be practiced otherwise than as specifically described.

I claim:

1. In a writing instrument including an elongated barrel provided with a writing tip at its forward end and a removable plastic cap provided with an openend to receive the forward end of said barrel to cover the writing tip when the instrument is not in use, the provision of improved and positive means to secure the cap on the barrel with an audible snap fit comprising: r

a circumferential recess on said barrel, said'recess including a pair of shoulders facing forwardly and rearwardly and spaced from each other;

a generally cylindrical, metallic ring providedwith a stop flange extending radially outward from a rear edge of the ring, said ring being positioned in the recess with said flange in contact with the forwardly facing shoulder, said cylindrical ring having at least one slot extending axially rearwardly from the forward edge thereof, said ring being provided with a plurality of circularly spaced, outwardly domed pro jections axially spaced from the stop flange;

a cylindrical metallic band having one edge portion attached to the plastic cap adjacent the open end thereof and a free edge portion beyond such open end, said free edge portion being provided with an inwardly directed lip having an-inner diameter smaller than a diameter defined by the outermost portions of the outwardly domed projections of the barrel ring, said lip being spaced from the open end of the cap and having an axial length smaller than'the distance arating the outermost portions of the domed projec- References Cited iliiiiiiliiil? 33353311'lfifilf igllfi iiii UNITED STATES PATENTS said projections and into forcible audible snap fit with 2782762 2/1957 yolfng 4O 1 '247 said flange to securely hold the cap on said barrel. 5 2,468,847 5/1949 Trafnor 285-319 2. The improvement of claim 1 wherein said radially ig i g i g l 8 outwardly extending stop flange is integral with said gen- 7 9/ 9 9 (mg 4 1-2 erally cylindrical metallic ring. FOREIGN PATENTS 3. The improvement of claim 1 wherein said cylindrical 944 2 1 1 4 France 401 243 metallic ring includes three circularly spaced outwardly 10 2,597 2/1906 Gr t Britain 401-247 domed projections and three axially rearwardly extending slots positioned intermediate said projections. LAWRENCE CHARLES, Primary Examiner 

